FIG. 1 depicts a flow chart of a conventional method for fabricating a read transducer used in magnetic recording technology applications. The conventional read transducer includes shields, magnetic bias structures, and a sensor. The read sensor is between the shields in the down track direction and between the magnetic bias structures in the cross-track direction. The read sensor is typically a giant magnetoresistive (GMR) sensor or tunneling magnetoresistive (TMR) sensor. The read sensor typically includes an antiferromagnetic (AFM) layer, a pinned layer on the AFM layer, a nonmagnetic spacer layer, and a free layer. In addition, seed layer(s) are typically be used. The free layer has a magnetization sensitive to an external magnetic field. Thus, the free layer functions as a sensor layer for the magnetoresistive sensor.
The bottom shield is deposited, via step 12. Step 12 typically includes depositing a soft material, such as NiFe. A layer of CoFeB is deposited, via step 14. CoFeB is typically amorphous as-deposited. A NiFe magnetic seed layer is then deposited, via step 16. The amorphous CoFeB layer thus separates the NiFe in the magnetic seed layer from the NiFe in the shield.
After deposition of the NiFe magnetic seed layer in step 16, the substrate for the reader is heated, via step 18. The substrate is heated to nominally two hundred eighty-five degrees Celsius. Thus, the portion of the read transducer that has been fabricated is heated to approximately two hundred eighty five degrees Celsius. While the substrate is heated, the AFM layer for the sensor is deposited, via step 20. The heating is then typically terminated.
The remainder of the sensor stack is deposited, via step 22. Thus, the tunneling barrier or conductive spacer layer and free layer are provided in step 22. The sensor is defined, via step 24. Step 24 typically includes masking the layers that have been deposited and milling the exposed layers. Thus, the track width in the cross track direction and the stripe height in a direction perpendicular to the ABS may be defined. The magnetic bias structures and top shield are also provided.
Although the method for fabricating conventional transducer functions, there are drawbacks. The exchange coupling between the AFM layer and the pinned layer, as measured by the exchange field (the shift in the hysteresis loop for the pinned layer) may be lower than desired. The quality of the tunneling barrier layer deposited in step 22 may not be as desired. Accordingly, what is needed is a system and method for improving the performance of a magnetic recording read transducer.